非离子型活性乳化剂及其水性环氧树脂的制备和性能

以α-甲氧基-ω-N-异丙醇基-对苯甲胺基聚乙二醇和酚醛环氧树脂F51为原料合成了非离子型活性乳化剂(PEGF51),并与F51混合,通过相反转法制备了分散相粒径为纳米级的PEGF51/F51水乳液.通过红外光谱和凝胶渗透色谱(GPC)分析了PEGF51的结构,研究了PEGF51浓度对PEGF51/F51水乳液分散相粒子粒径和D230-PEGF51/F51固化产物的力学性能、断面形貌和耐水性能的影响规律.结果表明:在环氧树脂分子结构中引入化学连接的PEG链段有利于提高环氧树脂链段的亲水性和应变松弛速率.增加PEGF51浓度,制备的PEGF51/F51水乳液分散相粒子粒径减小,粒度分布变窄;D230-PEGF51/F51固化产物的玻璃化转变温度和室温下的刚度和拉伸强度降低,冲击强度、断裂应变和吸水率增加.PEGF51与F51物质的量的比为1∶3时可制备出同时具有优异的拉伸强度、模量、断裂应变、冲击性能和低吸水率的D230-PEGF51/F51环氧树脂.     

Epoxy/Rectorite自由体积分布温度特性的正电子谱学研究

采用正电子寿命谱(PLA)技术,通过探测聚酰胺固化环氧树脂(Epoxy)及环氧树脂/累托土(Epoxy/Rectorite)复合材料分别在不同温度点自由体积分布特性的变化,结果表明:在低温T=30K时,分子链段被冻结,自由体积分布变窄;温度在T_g及以上时,聚酰胺固化DGEBA环氧树脂中出现微相分离情况,观测到两种大小不同的自由体积孔洞的存在;纳米复合材料中累托土片层与高分子链段相互作用,同时片层促进了环氧树脂的交联,阻碍了复合材料的微相分离.     

动态固化聚丙烯/环氧树脂共混物的研究

将动态硫化技术应用于热塑性树脂 热固性树脂体系 ,制备了动态固化聚丙烯 (PP) 环氧树脂共混物 .研究了动态固化PP 环氧树脂共混物中两组分的相容性、力学性能、热性能和动态力学性能 .实验结果表明 ,马来酸酐接枝的聚丙烯 (PP g MAH)作为PP和环氧树脂体系的增容剂 ,使分散相环氧树脂颗粒变细 ,增加了两组分的界面作用力 ,改善了共混物的力学性能 .与PP相比 ,动态固化PP 环氧树脂共混物具有较高的强度和模量 ,含 5 %环氧树脂的共混物拉伸强度和弯曲模量分别提高了 30 %和 5 0 % ,冲击强度增加了 15 % ,但断裂伸长率却明显降低 .继续增加环氧树脂的含量 ,共混物的拉伸强度和弯曲模量增加缓慢 ,冲击强度无明显变化 ,断裂伸长率进一步降低 .动态力学性能分析 (DMTA)表明动态固化PP 环氧树脂共混物是两相结构 ,具有较高的储能模量 (E′)     

含介晶单元的反应性增韧剂改性环氧树脂研究

合成了既含聚乙二醇醚(PEG)柔性链、又含刚性液晶结构单元的活性增韧促进剂(LCEU_PEG),对其促进环氧树脂/双氰双胺体系的固化反应活性、反应机制;增韧剂的用量与动态力学性能、冲击性能之间的关系进行了研究.结果表明:LCEU_PEG对E-51/dicy固化体系具有明显的促进作用,能有效的降低固化反应活化能及固化反应温度;改性体系的冲击强度较单纯的E-51/dicy体系提高3～7倍;模量较未增韧体系有所提高.     

含聚醚间隔链的扩链脲改性环氧树脂/双氰双胺固化体系性能研究

合成了一系列含不同分子量聚环氧丙烷 (PPG)柔性间隔链的扩链脲 ,系统考察了扩链脲改性环氧树脂E 5 1/双氰双胺 (dicy)固化体系的固化反应活性、动态力学行为、冲击性能和断裂面形态结构 ,并对体系的冲击性能、形态结构与动态力学行为之间的关系进行了探讨 .结果表明 ,改性体系固化反应活性明显提高 ,固化反应表观活化能降低 ,固化反应峰顶温度从 190℃降低至 14 0℃ ,固化反应的表观活化能由 14 5 5kJ/mol降至 70～ 80kJ mol;改性体系冲击强度明显提高 ,其中所含PPG柔性链分子量为 10 0 0的扩链脲改性的E 5 1/dicy体系冲击强度较未改性的E 5 1/dicy体系提高了 8倍 ,其冲击试样断裂面的形态具有明显的韧性断裂特征 ,微观两相网络结构的存在导致了改性体系冲击强度显著提高     

氨酯键扩链改性的669稀释剂对环氧树脂力学性能影响研究

制备了氨酯键扩链改性的669稀释剂UE6M,考察了加入不同用量的UE6M对环氧树脂进行稀释后环氧树脂混合体系的粘度变化。使用氰乙基化三乙烯四胺作为固化剂对环氧树脂混合体系进行固化,研究了UE6M的用量对环氧树脂混合体系固化物性能的影响。研究结果表明,UE6M对E51环氧树脂具有较好的稀释效果,且混合体系固化产物的韧性较纯环氧树脂固化物明显增强:UE6M用量为30%和40%的混合体系粘度仅为纯E51环氧树脂粘度的6.35%和1.43%,但其固化物的拉伸强度均在60MPa以上,分别为纯E51环氧树脂固化物的87.9%和80.9%。断裂伸长率均为纯环氧树脂固化物的8倍以上,弯曲应变为纯环氧树脂固化物2倍以上,弯曲强度及弯曲模量等未出现大幅下降,UE6M稀释剂加入环氧树脂后固化产物的韧性得到明显增强。     

新型复合环氧光学树脂的制备与性能研究

通过2,2-二巯基乙硫醚(MES)与环氧氯丙烷反应合成了2,2-二巯基二乙硫醚二缩水甘油醚型环氧树脂(DGEMES),通过FTIR和MS对其进行表征;用乙二胺作为固化剂,将DGEMES与双酚A型环氧树脂(DGEBA)复合固化,得到了新型高折射率和低色散的光学树脂.DGEMES是一种较好的共聚单体,可以同时提高共聚树脂的折射率和阿贝数;DGEBA/DGEMES/乙二胺共固化树脂的nd=1.59～1.62,νd=35～39;当DGEMES的质量分数为40%时,固化树脂的折射率达到1.60以上,冲击强度22.5kJ/m₂,且其它性能较均衡.此外,以甲基六氢苯酐(B-650)为固化剂,还合成了具有中等折射率的DGEBA/DGEMES/B-650共固化树脂(nd=1.54～1.56,νd=38～40),并对其光学和机械性能进行了研究.     

咪唑封端聚氨酯予聚体改性环氧树脂E-51/双氰双胺固化体系性能研究

以聚丙二醇PPG10 0 0、甲苯二异氰酸酯 (TDI)、咪唑为原料 ,合成了咪唑封端的聚氨酯予聚体 ,简称扩链脲TIEU .利用DSC、粘弹谱仪、冲击试验机及扫描电镜 (SEM)等手段对TIEU改性的环氧树脂E 5 1/双氰双胺(dicy)固化体系的反应活性、动态力学行为、冲击性能、断裂面形态结构进行了系统研究 .实验结果表明 ,改性后的E 5 1 dicy体系反应活性明显提高 ,固化反应的表观活化能由未改性体系的 131kJ mol降至 75～ 80kJ mol.与咪唑促进体系比较结果显示 ,两种固化反应的促进机制具有一定的差异 .另外与未改性体系相比 ,经过改性的环氧树脂体系冲击强度提高 2～ 3倍 ,而玻璃化温度和模量基本不变 ,冲击断面呈韧性断裂     

在Bu_2SnO-Bu_3PO_4缩合物的存在下以端羟基聚醚增韧环氧树脂

工业中大量生产的端羟基聚醚 ,由于羟基的反应活性不够 ,不能直接用于增韧胺类固化的环氧树脂 .Bu2 SnO Bu3PO4 缩合物能催化羟基对环氧基的加成反应 .本文研究在Bu2 SnO Bu3PO4 缩合物Sn P6 70 0的存在下以端羟基聚四氢呋喃 (PTMG)增韧芳香胺 4,4′ 二氨基二苯砜 (DDS)固化的环氧树脂 .PTMG首先与环氧树脂反应生成嵌段共聚物 ,在固化时发生微相分离 .分散相的尺寸在有利于增韧的范围内 .PTMG在分子量与浓度适当时 ,能使树脂的断裂韧性大大提高 ;抗弯强度也有显著提高 ,而Tg 和模量略有降低 .     

刚性链嵌段共聚物的研究(I)——聚醚醚酮-聚醚砜嵌段共聚物结构与性能

本文以聚醚醚酮(PEEK)和聚醚砜(PES)齐聚物为原料,通过溶液缩聚法制备PEEK-PES嵌段共聚物,并用DSC、TGA、WAXD和动态粘弹谱等手段对其相容性、结晶行为、动态力学性能和热性能进行了研究.结果表明,嵌段共聚物在PEEK链段M_n=1×10⁴,PES链段M_n)=3500～250(PES含量为25.0%～2.9%)组成范围内不产生微相分离,保持了结晶性能,其玻璃化转变温度比纯PEEK提高将近20℃,并具有较好的高温力学性能.     

Mechanical properties and curing kinetics of epoxy resins cured by various amino-terminated polyethers

<正>A high performance thermosetting epoxy resin crosslinkable at room temperature was obtained via directly moulding diglycidyl ether of bisphenol A(DGEBA) and flexibleα,ω-bisamino(n-alkylene)phenyl terminated poly(ethylene glycol).The influences of the n-alkylene inserted in aminophenyl of flexible amino-terminated polythers(ATPE) on the mechanical properties,fractographs and curing kinetics of the ATPE-DGEBA cured products were studied.The results show that the insertion of n-alkylene group into the aminophenyl group of the ATPE,on one hand,can significantly increase the strain relaxation rate and decrease glass transition temperature of the ATPE-DGEBA cured products,resulting in slight decrease of the Young's modulus and tensile strength,and significant increase of the toughness and elongation of the ATPE-DGEBA cured products.On the other hand,it can remarkably enhance the reactivity of amine with epoxy,much accelerating the curing rate of the ATPE-DGEBA systems.The activation energy of DGEBA cured by BAPTPE,BAMPTPE and BAEPTPE was 53.1,28.5 and 25.4 kJ·mol~(-1),respectively.The as-obtained ATPE-DGEBA cured products are homogeneous, transparent,and show excellent mechanical properties including tensile strength and toughness.Thus they are promising to have important applications in structure adhesives,casting bulk materials,functional coatings,cryogenic engineering, damping and sound absorbing materials.     

Nanoscale confinement effects on the relaxation dynamics in networks of diglycidyl ether of bisphenol-A and low-molecular-weight poly(ethylene oxide)

Thermoplastic poly(ethylene oxide) (PEO) (Mw(PEO) approximately 4000) has been used to prepare thermosetting nanocomposites incorporating diglycidyl ether of bisphenol A (DGEBA) epoxy oligomer. Blends with various PEO/DGEBA weight ratios were cured using stoichiometric portions of 4,4'-diaminodiphenylmethane. The resulting semi-interpenetrating polymer networks were studied by several techniques. Nanoscale confinement effects, thermal (glass transition, melting and crystallization temperatures) and structural features of our materials are similar to those for networks with much higher Mw(PEO) and different curing agents; however, the polyether crystallization onset occurs in our case at a lower PEO concentration; shorter PEO chains organize themselves more easily into crystalline domains. Very low estimates of the k parameter of the Gordon-Taylor equation, used to fit the compositional dependences of the dielectric and calorimetric glass transition temperatures, and a strong plasticization of the motion of the glyceryl segments (beta-relaxation) in the epoxy resin were observed. These illustrate an intensified weakening in the strength of the intermolecular interactions in the modified networks, as compared to the high strength of the self-association of hydroxyls in the neat resin. The significance of hydrogen-bonding interactions between the components for obtaining structurally homogeneous thermoset-i-thermoplastic networks is discussed.     

Epoxy resin/poly(ethylene oxide) (PEO) and poly(ε-caprolactone) (PCL) blends cured with 1,3,5-trihydroxybenzene: miscibility and intermolecular interactions

Epoxy resin (ER)/poly(ethylene oxide) (PEO) and/or poly(e-caprolactone) (PCL) blends cured with 1,3,5-trihydroxybenzene (THB) were prepared via the in situ curing reaction of epoxy monomers in the presence of PEO and/or PCL, which started from the initially homogeneous mixtures of DGEBA, THB and PEO and/or PCL. The miscibility and the intermolecular specific interactions in the thermosetting polymer blends were investigated by means of differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The two systems displayed single and composition-dependant glass transition temperatures (T _gs), indicating the full miscibility of the thermosetting blends. The experimental T _gs of the blends can be well accounted for by Gordon-Taylor and Kwei equations, respectively. The T _g-composition behaviors were compared with those of poly(hydroxyether of bisphnol A) (Phenoxy) blends with PEO and PCL. It is noted that the formation of crosslinked structure has quite different effects on miscibility and intermolecular hydrogen bonding interactions for the thermosetting polymer blends. In ER/PEO blends, the strength of the intermolecular hydrogen bonding interactions is weaker than that of the self-association in the control epoxy resin, which is in marked contrast to the case of Phenoxy/PEO blends. This suggests that the crosslinking reduces the intermolecular hydrogen bonding interactions, whereas the intermolecular hydrogen bonding interactions were not significantly reduced by the formation of the crosslinking structure in ER/PCL blends.     

Morphology,thermo-mechanical properties and surface hydrophobicity of nanostructured epoxy thermosets modified with PEO-PPO-PEO triblock copolymer

In this paper, we report on the effect of amphiphilic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer (TBCP) on the miscibility, phase separation, thermomechanical properties and surface hydrophobicity of diglycidyl ether of bisphenol-A (DGEBA)/4,4'-diaminodiphenylmethane (DDM) system. The blends were nanostructured. The phase separation occurred via self-assembly of PPO blocks followed by the reaction induced phase separation of PEO blocks. The surface roughness increased with increase in concentration of TBCP due to increased phase separation of PEO blocks at higher concentration. The phase separated PEO blocks formed the crystalline phase in the amorphous crosslinked epoxy matrix. The TBCP has a strong plasticizing effect on the matrix and decreased the glass transition temperature (T_g) and modulus of the thermoset. The incorporation of TBCP improved impact strength and tensile properties and 5 phr TBCP content was found to be optimum to achieve balanced mechanical performance. Moreover, the thermal stability of the epoxy system was retained while hydrophobicity was improved in the presence of TBCP.     

Morphology,toughness mechanism,and thermal properties of hyperbranched epoxy modified diglycidyl ether of bisphenol A (DGEBA) interpenetrating polymer networks

New hyperbranched poly(trimellitic anhydride‐triethylene glycol) ester epoxy (HTTE) is synthesized and used to toughen diglycidyl ether of bisphenol A (DGEBA) 4,4′‐diaminodiphenylmethane (DDM) resin system. The effects of content and generation number of HTTE on the performance of the cured systems are studied in detail. The impact strength is improved 2–7 times for HTTE/DGEBA blends compared with that of the unmodified system. Scanning electron microscopy (SEM) of fracture surface shows cavitations at center and fibrous yielding phenomenon at edge which indicated that the particle cavitations, shear yield deformation, and in situ toughness mechanism are the main toughening mechanisms. The dynamic mechanical thermal analyzer (DMA) analyses suggest that phase separation occurred as interpenetrating polymer networks (IPNs) for the HTTE/DGEBA amine systems. The IPN maintains transparency and shows higher modulus than the neat epoxy. The glass transition temperature (T_g) decreases to some extent compared with the neat epoxy. The T_g increases with increase in the generation number from first to third of HTTE and the concentrations of hard segment. The HTTE leads to a small decrease in thermal stability with the increasing content from TGA analysis. The thermal stability increases with increase in the generation number from first to third. Moreover, HTTE promotes char formation in the HTTE/DGEBA blends. The increase in thermal properties from first to third generation number is attributed to the increase in the molar mass and intramolecular hydrogen bridges, the increasing interaction of the HTTE/DGEBA IPNs, and the increasing crosslinking density due to the availability of a greater number of end hydroxyl and end epoxide functions. Copyright © 2008 John Wiley & Sons, Ltd.     

一种新型室温固化、耐高温环氧树脂体系及其性能

采用1-己基-3-甲基咪唑四氯化铁盐([C₆mim]FeCl₄)与混合胺复配室温(20 ℃)固化双酚A型环氧树脂E-51,并与其它脂肪胺类室温固化E-51体系在力学性能、热性能、耐老化性能方面的数据进行了比较,同时分析了[C₆mim]FeCl₄不同添加量对固化体系性能的影响,结果显示:[C₆mim]FeCl₄/混合胺复配室温固化E-51体系的室温拉伸强度可达90 MPa,高温(120 ℃)下也保持了良好的力学性能,热失重(5%)分解温度为310 ℃,200 ℃老化7 d后,拉伸强度为28 MPa,是一种可在高温下使用的新型环氧树脂室温固化体系。     

Mechanical and Thermal Properties and Morphology of Epoxy Resins Modified by a Silicon Compound

A silicon compound (GAPSO) was synthesized to modify the diglycidyl ether of bisphenol-A (DGEBA). The chemical structure of GAPSO was confirmed using FT-IR, ²⁹Si NMR and GPC. The mechanical and thermal properties and morphologies of the cured epoxy resins were investigated by impact testing, tensile testing, differential scanning calorimetry and environmental scanning electron microscopy. The impact strength and tensile strength were both increased by introducing GAPSO, meanwhile the glass transition temperature (T_g ) was not decreased and the morphologies of the fracture surfaces show that the compatibility of GAPSO with epoxy resin was very good and the toughening follows the pinning and crack tip bifurcation mechanism. The high functional groups in GAPSO can react during the curing process, and chemically participate in the crosslinking network. GAPSO is thus expected to improve the toughness of epoxy resin, meanwhile maintain the glass transition temperature.     

Studies on Surface Free Energy of an Anhydride-Epoxy Cured System: Effect of Side Alkenyl Chain Length of Hardener on Tensile and Impact Properties

Three kinds of alkenyl succinic anhydrides (ASA) with varying side chain lengths (2-octenyl, 2-dodecyl, and 2-hexadecynyl succinic anhydrides) for hardeners as epoxy curing agents are synthesized by the ene reaction. The curing effect of ASA on the mechanical tensile and impact properties of cured diglycidyl ether of bisphenol-A (DGEBA) epoxy resin is studied. It is observed that increasing the side alkenyl chain length of ASA leads to a decrease of tensile strength of the cured epoxy resin, probably due to the decreasing of cross-linking density. However, it is found that the impact properties of the casting specimens are increased as the side alkenyl chain length of the hardener increases. This is probably due to the effect of the nonpolar or London-dispersive component of the surface free energy of the ASA studied, resulting in improving of the toughness properties of the casting specimens. Copyright 2000 Academic Press.